Antennas are commonly required in nautical and aeronautical applications for the purposes of communicating with an aircraft or boat. It is often advantageous to have multiband antennas in these applications so that a reduced number of antennas are required for communications on all required frequency bands. U.S. Pat. No. 5,621,420 shows an example of a duplex monopole antenna for use with aircrafts, vehicles and marine vessels. This antenna design however is not aerodynamic and therefore may not be well suited for vehicular, aeronautical, or nautical applications. U.S. Pat. No. 7,746,282 shows an example of a more compact multiband antenna for aircraft applications.
Blade antennas, in particular, are commonly used in nautical and aeronautical applications due to their compact and aerodynamic footprint relative to other types of antennas such as monopole, dipole or whip antennas. Blade antennas can also be designed and constructed for receiving and radiating at multiple bands or over a very wide band. Blade antennas further provide the advantage of being more mechanically robust in presence of vibrations experienced during operation on aircrafts compared to many other types of antennas. Blade antennas are typically constructed by providing metal traces on one or both sides of an insulated board, such as an FR-4 circuit board or a fiber glass circuit board. These traces are of dimensions to provide resonance in the particular targeted frequency bands of the antenna. U.S. Pat. No. 7,633,451 shows an example of a blade type multiband antenna for aircraft applications.